Vapor generator mixing section support

ABSTRACT

A support is provided for a pressurized wall of a once-through vapor generator in which mixing headers are positioned exteriorly of the wall. The support extends transversely across and is secured to the tubes which connect the mixing headers in flow communication.

United States Patent [19] Pratt et al.

145] May 7,1974

[ VAPOR GENERATOR MIXING SECTION SUPPORT [75] Inventors: Harry M. Pratt, West Orange;

Byram J. Magol, Convent Station; Dudley P. Money, Parsippany, all of NJ.

[73] Assignee: Foster Wheeler Corporation,

Livingston, NJ.

22 Filed: May 29,1973

21 Appl.No.: 364,393

Related US. Application Data [63] Continuation of Ser. No. 210,687, Dec. 22, 1971,

abandoned. I

[52] US. Cl. 122/510, 122/6 A [51] Int. Cl. F22b 37/24 [58] Field of Search 122/6 A, 235 A, 494, 510

[5 6] References Cited UNITED STATES PATENTS 3,665,893 5/1972 Barberton 122/510 3,324,837 6/1967 Gorzegno et al l22/510 3,444,841 5/1969 Cooper et al. 122/510 Primary Examiner-Kenneth W. Sprague Attorney, Agent, or Firm-Marvin A. Naigur, Esq.; John E. Wilson, Esq.

[57] ABSTRACT A support is provided for a pressurized wall of a oncethrough vapor generator in which mixing headers are positioned exteriorly of the wall. The support extends transversely across and is secured to the tubes which connect the mixing headers in flow communication.

2 Claims, 10 Drawing Figures PATENTED m 7 1914 SHEET 1 BF 2 ike I 78 |Ll 2 -40 ITITITITITITITIT INVENTORS HARRY H .PRATT BYRAM J. MA DUDLEY P. MO EY GOL AT OR PATENTEUIAY 7 m4 SHEET 2 1F 2 FIG. 7

FIG. /0

VAPOR GENERATOR MIXING SECTION SUPPORT CROSS-REFERENCE TO RELATED APPLICATION The present application is a continuation of application Ser. No. 210,687 filed Dec. 22, 1971 and now abandoned.

BACKGROUND OF THE INVENTION In the fabrication of vapor generators which are used in power generating system, it is necessary to provide an arrangement for sealing the wall of the generator in the area in which the wall tubes extend outwardly from the wall. The support arrangement of the instant invention is particularly useful to support the lower furnace in vapor generators having a furnace section which is divided into upper and lower portions, with the upper portion being top supported. In this type of vapor generator, alternate tubes of the upper and lower portions usually extend through a common plane so that parts of the tubes are coextensive and interlaced with each other. It has been the general practice to weld the coextensive and interlaced portions of the tubes by means of elongated plates disposed between the tube interspaces, such that the lower portion of the furnace is supported by the upper portion, with the tubes bent outwardly from the furnace wall and connected to suitably arranged headers.

The instant invention contemplates providing a support section which is transversely positioned with respect to the tube axes and secured to the upper and lower portions of the furnace. In this manner it is possible to avoid using welded connections contiguous to the tubes, thereby making it possible to more easily fabricate a welded seal arrangment and minimize the thermal stresses at the seal location.

It should be noted that the support member of the instant invention is subjected to compression forces, as will more fully be described herein, whereas in the elongated plate arrangement between the tubes which has heretofore been used, the welded connections between the tubes and webs are subject to shear forces. Accordingly, by establishing a force pattern in compression, as in the instant invention, a superior structural configuration is obtained as compared with the prior plate structure with its attendant shear forces.

A further advantage attendant to the instant invention is the ability to locate the mix headers closer to the wall of the vapor generator than has heretofore been possible with the plate structure of the prior art. This is due to the fact that prior plate structure resulted in relatively high tube temperatures, which required the headers to be located a substantial distance from the vapor generator wall in order to absorb the temperature differential.

A still further advantage resulting from the instant invention resides in the ability to utilize a series of individual support members around the periphery of the furnace. This is possible since the instant support arrangement serves only the function of carrying the load, whereas the prior plate structure serves as both a load carrying part as well as a furnace pressure containment part. Accordingly, the plate structure requires a continuous web surrounding the periphery of the fur nace. Since the lower furnace and upper furnace have different temperatures, the use of a plate structure results in a third average temperature resulting in attendant differences in thermal expansion along the periphery of the web. This is not the case in connection with the support section of the instant invention, since the temperature absorption in the area of the support section is relatively minimal as compared with the prior plate structure, and also in view of the plurality of individual support members surrounding the periphery of the boiler as opposed to the continuous web used with the prior plate arrangement.

It should also be noted that large forced-flow vapor generators generally have a tendency to have different cross-sectional thermal expansion, starting from the bottom of the furnace and ascending to the top. This difference in cross-sectional thermal expansion is much easier to translate from the lower furnace to the upper furnace with the support arrangement of the instant invention that does not require welding along interlaced tubes between the furnace sections as is the case with the prior plate structure. Thus, the support section of the present invention allows the furnace to grow due to thermal expansion without constraining such expansion at the junction between the lower and upper furnace.

SUMMARY OF THE INVENTION In accordance with an illustrative embodiment demonstrating features and advantages of the present invention, there is provided support means in a forced circulation fluid heating unit which includes upright walls forming a furnace for the flow of heating gases. Means are provided for supplying high temperature heating gases to the furnace, and the walls include a first group of upwardly extending, laterally spaced fluid heating tubes rigidly united by metallic webs disposed in the intertube spaces to form a lower portion of the wall. A second group of upwardly extending, laterally spaced fluid heating tubes is arranged for parallel flow of fluids therethrough and rigidly united by metallic webs disposed in the intertube spaces to form an upper portion of the wall and having their longitudinal axes aligned with the longitudinal axes to tubes of the first group. Header means communicate with, receive, and mix fluids flowing from tubes of the first group and distribute mixed fluids to the tubes of the second group. Means are provided for supplying fluid to tubes of the first group, with the first and second groups of tubes being constructed and arranged to provide flow of fluid in the furnace only in an upward direction. Some of the tubes of the first and second tube groups are bent out of the plate of the wall at first and second levels, respectively, for connection to the header means and interlace with and laterally spaced from each other in the plane of the wall betweenthe first and second levels, with the second level being subjacent the first level. The support means transversely extend across the longitudinal axes of the tubes and are positioned exteriorly of the spaces between the interlaced tubes. The support means are secured to the first and second groups of tubes whereby the load from the first group of tubes is transferred exteriorly of the spaces to the support means and then to the second group of tubes, such that the interlaced tubes are not weld united and the first and second groups of tubes generate a force in compression along the support means.

BRIEF DESCRIPTION OF THE DRAWINGS The above brief description, as well a further objects, features, and advantages of the present invention will be more fully appreciated by reference to the following detailed description of a presently preferred but nonetheless illustrative embodiments in accordance with the present invention, which taken in connection with the accompanying drawings wherein:

FIG. 1 is a diagrammatic sectional view of a vapor generator wall showing the channel support and mix header;

FIG. 2 is an elevational view of the wall of FIG. 1, with portions of the wall being broken away to show the channel support;

FIG. 3 is an enlarged sectional view of the channel support and a portion of the wall shown in FIG. 1;

FIG. 4 isa front elevational view of a portion of the channel support and wall shown in FIG. 3;

FIG. 5 is an enlarged sectional view of a portion of a beam support in accordance with another embodiment of the invention;

FIG. 6 is a front elevational view of a portion of the I beam support and wall shown in FIG. 5;

FIG. 7 is an elevational view of a portion of the tubes shown in FIG. 4 with the channel support removed in order to illustrate a heat shield arrangement;

F IG. 8 is an enlarged sectional view of a fin-tube wall construction of a portion of the vapor generator;

FIG. 9 is an enlarged sectional view of a tangent tube and skin-casing wall construction of a portion of the vapor generator; and

FIG. 10 is an enlarged sectional view of a tangent tube and filler bar wall construction of a portion of the vapor generator.

DESCRIPTION OF THE PREFERRED EMBODIMENT With reference to FIG. I, in accordance with the present invention there is provided a support arrangement generally designated 10 in the form of channel members 12 which are part of a vapor generator 14 having a furnace section 16 which isdefined by wall panels 18. As best shown in FIGS. 4 and 10, the walls 18 are formed from tubes 20 and fins 21 which are welded together. It should be understood that the allwelded walls 18 may also be fabricated, as shown in FIG. 11, with the tubes 20 brought together tangentially with an exterior skin-casing 22, or as shown in FIG. 12 withthe tubes 20 brought together tangentially with filler bars 23. Means for supplying high temperature heating gases are schematically represented in FIG. 1 by a directional arrow 24, and means for supplying fluid to the tubes 18 are designated by a directional arrow 25.

Details of the generator walls 18 are described in copending application Ser. No. 613,632, filed Feb. 2,

1967, by Walter P. Gorzegno, Frederick H. Weber, and Robert H. Pai, entitled Multiple Pass Design for Once- Through Steam Generators. Application Ser. No. 613 ,632 was in turn a divisional of US. application Ser. No. 370,604, filed May 27, 1964, by the abovementioned inventors, now US. Pat. No. 3,324,837.

In essence, the above-mentioned copending application and patent relate to a once-through vapor generator which utilizes the Benson principle, wherein heated riser tube circuits are coupled to unheated downcomer circuits in the furnace enclosure wall. In recent years the Benson principle has been utilized in vapor generators having an all-welded wall construction as respectively shown in FIGS. 8, 9 and 10, wherein parallel tubes of the combustion chamber are seal welded together, providing a gas-tight construction. However, the all-welded wall construction created serious stress and sealing problems in instances where the wall was penetrated by tubes passing either through the wall or into the wall, at an angle thereto. Such instances may arise when superheater tubes pass through the membrane wall, or more often in the connection of flow passes of the furnace section.

In the copending patent application and patent referred to above, a furnace circuitry was described in which a plurality of flow passes in series relationship with each other define the vapor generator furnace section. At least one of the passes occupies the upper portion of the furnace enclosure, and the other passes occupy the lower portion of the furnace enclosure. The furnace enclosure is top supported by suitable frame work or structure outside of the vapor generator. Headers for the upper and lower portion passes are disposed outside of the furnace periphery in the area of the junction between the upper and lower portions, and the tubes of the upper and lower portion passes are bent outwardly from the plane of the enclosure for connection to the headers.

Turning again to FIGS. 1 and 4, the tubes 20 include a lower tube wall 26 and upper tube wall 28 which respectively define the lower portion and upper portion of the furnace 16. A lower mix header 30 and upper mix header 32 are connected in flow communication with the lower tube wall 26 and upper tube wall 28. By progressively inspecting FIGS. 1 and 2, it can be appreciated that a portion of the lower tubes 26, which have been designated 26A, are bent outwardly along a lower level 34 and connected to the lower mix header 30. The remaining tubes 26 of the lower portion of the furnace 16, which have been designated B, extend upwardly to an upper level 36 where they are bent outwardly from the furnace wall 16 and then pass down for connection with the lower header 30. The upper tubes 28 diverge in an area of the upper level 36, in a manner similar to the divergence of the lower tubes 26. Accordingly, a first group of the tubes 28, which has been designated 28A, bend outwardly along the upper level 36 and extend to the header 32, and the remaining portion of the upper tubes 28, which have been designated 28B, pass on downwardly so that they are coextensive with and interlaced with the tubes 26B in a common plane intermediate the walls 18. Thus, it can be seen that the tubes 28B are bent outwardly along the lower plane 34 for connection with mix header 32.

As can be seen in FIGS. 2 and 3, the support arrangement 10 comprises a series of individual channel members 12 which extend around the periphery of the furnace 16. Each of the channels 12 has C-shaped crosssection and is formed with a web 40 and spaced apart outwardly extending upper flanges 42 and lower flanges 44. It is preferable to provide a stiffening member 46 for each of the channels 12 which is welded between the flanges 42 and 44. A series of lower lugs 49 and upper lugs 50 are welded to and respectively extend outwardly from the flanges 42 and 44 for the purpose of transferring the load from the lower tubes walls 26 through the channel 12 to the upper tube walls 28.

This is accomplished by welding the upper lugs 50 to the tubes 26B and the lower lugs 48 to the tubes 28B, such that the load from the entire lower furnace tube wall 26 is transferred to the channel 12 which in turn transfers the load to the upper tube walls 28 which are top supported. By locating lower lugs 48 to the upper furnace tubes 28B at the bottom of the channel 12 and the upper lugs 50 to the lower furnace tubes 26B at the top of the channel 12, the welded connections between lugs 48, 50 and channel 12 are always maintained in compression. Thus, the welds between the upper flanges 42 and upper lugs 50 connecting the tubes 263 with upper flanges 42, and the welds between the lower flanges 44 and lower lugs 48 connecting the tubes 283 with lower flanges 44, are respectively maintained in compression. This arrangement further affords flexibility to absorb temperature differentials between the tubes and between the channel 12 and other components of the seal which will hereafter be described.

In FIGS. 5 and 6 there is illustrated a further embodiment of the invention in which corresponding parts have been designated by the same reference numerals as part of a 100 series. In this form of the invention, a support arrangement generally designated 110, is provided in the form of beam members 112 which are part of the vapor generator 14. The support arrangement 110 comprises a series of individual beam members l 12 which extend around the periphery of furnace 16. Each of the beam members 112 has a substantially rectangular shape cross-sectional area and typical dimensions would be a length of 5 inches, a thickness of 1 inch, and a width of 48 inches. A series of lower lugs 156 and upper lugs 158 are welded to and respectively extend outwardly from beam member 112 for the purpose of transmitting the load from the lower tube walls 26 through the beam member 112 to the upper tube walls 28. In this connection, it should be noted that the upper lugs 158 and lower lugs 156 are positioned along the horizontal edges of beam member 112 and are secured by means of upper and lower horizontal fillet welds 160 which are formed along the outer surface of beam 112. By progressively comparing FIGS. 5 and 6, it can be appreciated that the load is transferred from the lower tube walls 26 to the upper tube walls 28 by welding the upper lugs 158 to the tubes 26B and the lower lugs 156 to the tubes 28B, such that the load from the entire lower furnace tube wall 26 is transferred to beam members 112 which in turn transfer the load to the upper tube walls 28 which are top supported. By locating the lower lugs 156 to the upper furnace tubes 288 at the bottom of the support members 112 and the upper lugs 158 to the lower furnace tubes 268 at the top of the beam members 112, the welded connections 160 between lugs 156, 158 and channel 112 are always maintained in compression.

In FIG. 1, there is shown upper seal channel 70 and lower seal channel 72 having an opening therein through which horizontally extending tube portions (26A, 28B, 26B, 28A) extend. A detailed description of this sealing arrangement can be found in US. Pat. No. 3,444,841 to Cooper et al. The seal channels 70 and 72 form a pressure'tight connection with the channel member 12 by means of upper seal plates 74 and lower seal plates 76 which are welded to flanges 42 and 44 of channel members 12 and the seal channels 70, 72. The plates 74 and 76 extend around the periphery of the furnace l4 and between each of the channel members 12 there is welded a seal member 78 as shown in FIG. 2. The seal channels and 72 are of similar construction for use with the beam member 112. In these embodiments of the support arrangement 110, the edges of plates 74 and 76 are bent toward the exterior surfaces of beam members 112, for welding thereto; or alternatively, the edges of plates 74 and 76 may extend across beam members 112 for welding together.

It should be noted that the tubes 20 of the upper furnace tube walls 28 are shown as having a smaller tube diameter than the tubes 20 of the lower furnace tube walls 26. In this connection, it should be understood that the support arrangements 10, 110 of the instant invention would be equally adaptable for tubes 20 having the same tube diameter for both the upper furnace tube walls 28 and lower furnace tube walls 26.

As shown in FIG. 9, a heat shield arrangement, generally designated 80 is mounted on the tubes 20. The heat shield arrangement 20 includes a pair of contiguous shielding plates 82 mounted between each pair of adjacent tubes 20 between the interior of the furnace section 16 which is coextensive with the respective support arrangements 10, 110. The shielding plates 82 are provided for protecting the support arrangements 10, 1 10 from being overstressed due to the heat created in the furnace section 16.

A latitude of modification, change and substitution is intended in the foregoing disclosure and in some instances some features of the invention will be employed without a corresponding use of other features. Accordingly, it is appropriate that the appended claims be construed broadly and in a manner consistent with the spirit and scope of the invention herein.

What is claimed is:

1. In a forced circulation vapor generator,

a plurality of vertically aligned parallel closely spaced water cooled tubes forming an upright planar surface having inner and outer sides, tee tubes having their intertube spaces closed in most part by metallic webs;

said tubes defining a lower furnace section and an upper'furnace section that is spaced apart from said lower furnace section in which some of said tubes from said lower furnace section and said upper furnace section penetrate said surface from a point outside of said surface at an angle thereto such that said tubes are interlaced between said upper fumace section and said lower furnace section;

header means positioned exteriorly of said planar surface and in flow communication with the penetrating tubes of said upper and lower furnace sections;

seal means having openings for said penetrating tubes to extend through and for forming a pressure-tight closure between said upper furnace section and said lower furnace section; the improvement comprising support means transversely extending across the axes of said tubes and positioned between said penetrating tubes of said upper furnace section and said lower furnace section, weld connections securing said support means between said upper furnace section and said lower fumace section between said penetrating tubes, said support means comprising a channel member having a C-shaped crosssectional configuration defined by a plate and opposing flange members, with one of said flange members rigidly fixed to said upper furnace section and the other of said flange members rigidly fixed to said lower furnace section, whereby the load weight of said lower furnace section is transferred through said channel member to said upper furnace section, such that said upper and lower furnace section generate a force in compression along said channel member.

2. In a forced circulation vapor generator,

a plurality of vertically aligned parallel closely spaced water cooled tubes forming an upright planar surface having inner and outer sides, the tubes having their intertube spaces closed in most part by metallic webs;

said tubes defining a lower furnace section and an upper furnace section is spaced apart from said lower furnace section in which some of said tubes from said lower furnace section and said upper furnace section penetrate said surface from a point outside of said surface at an angle thereto such that surface and in flow communication with the penetrating tubes of said upper and lower furnace sections; 7

seal means having openings for said penetrating tubes to extend through and for forming a pressure-tight closure between said upper furnace section and said lower furnace section; theimprovement comprising support means transversely extending across the axes of said tubes and positioned between said penetrating tubes of said upper furnace section and said lower furnace section,- would connections securing said support means between said upper furnace section and said lower furnace section between said penetrating tubes, said support means comprising a substantially flat beam, with one end of said beam rigidly fixed to said upper furnace section and the other end of said beam rigidly fixed to said lower furnace section, whereby the load weight of said lower furnace section is transferred through said beam to said upper furnace section, such that said upper and lower furnace section generate a force in compression along said beam.

UNITED STATES PATENT OFFICE CEHHCTE CF CORRECTION Patent No. 3 a 809 a 018 7 7 Dated lnventofls) Harry M. Pratt et a1.

It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 3, line 6, "which" should read 1: when Column 4 line 40 "B" should read 26B Column 8 line 12 "would" should read Weld r\-.

En'gncd and Sealed this second D ay Of September 19 75 [SEAL] A ttes r:

C. MARSHALL DANN ('mnmissivncr of Pulenls and Trademarks:

RUTH C. MASON Alluring Officer FORM PO-105O (10-69) USCOMM-DC fiO376-P69 U.S. GOVERNMENY PRlNTlNG OFFICE I B 9 9 o 

1. In a forced circulation vapor generator, a plurality of vertically aligned parallel closely spaced water cooled tubes forming an upright planar surface having inner and outer sides, tee tubes having their intertube spaces closed in most part by metallic webs; said tubes defining a lower furnace section and an upper furnace section that is spaced apart from said lower furnace section in whicH some of said tubes from said lower furnace section and said upper furnace section penetrate said surface from a point outside of said surface at an angle thereto such that said tubes are interlaced between said upper furnace section and said lower furnace section; header means positioned exteriorly of said planar surface and in flow communication with the penetrating tubes of said upper and lower furnace sections; seal means having openings for said penetrating tubes to extend through and for forming a pressure-tight closure between said upper furnace section and said lower furnace section; the improvement comprising support means transversely extending across the axes of said tubes and positioned between said penetrating tubes of said upper furnace section and said lower furnace section, weld connections securing said support means between said upper furnace section and said lower furnace section between said penetrating tubes, said support means comprising a channel member having a C-shaped cross-sectional configuration defined by a plate and opposing flange members, with one of said flange members rigidly fixed to said upper furnace section and the other of said flange members rigidly fixed to said lower furnace section, whereby the load weight of said lower furnace section is transferred through said channel member to said upper furnace section, such that said upper and lower furnace section generate a force in compression along said channel member.
 2. In a forced circulation vapor generator, a plurality of vertically aligned parallel closely spaced water cooled tubes forming an upright planar surface having inner and outer sides, the tubes having their intertube spaces closed in most part by metallic webs; said tubes defining a lower furnace section and an upper furnace section is spaced apart from said lower furnace section in which some of said tubes from said lower furnace section and said upper furnace section penetrate said surface from a point outside of said surface at an angle thereto such that said tubes are interlaced between said upper furnace section and said lower furnace section; header means positioned exteriorly of said planar surface and in flow communication with the penetrating tubes of said upper and lower furnace sections; seal means having openings for said penetrating tubes to extend through and for forming a pressure-tight closure between said upper furnace section and said lower furnace section; the improvement comprising support means transversely extending across the axes of said tubes and positioned between said penetrating tubes of said upper furnace section and said lower furnace section, would connections securing said support means between said upper furnace section and said lower furnace section between said penetrating tubes, said support means comprising a substantially flat beam, with one end of said beam rigidly fixed to said upper furnace section and the other end of said beam rigidly fixed to said lower furnace section, whereby the load weight of said lower furnace section is transferred through said beam to said upper furnace section, such that said upper and lower furnace section generate a force in compression along said beam. 